What’re the principle for using pre-stressing force method of gantry crane?
Principle for using pre-stressing force method of gantry crane to correct main girder down-warp: use pre-stressing force to stretch-draw many
steel bars or steel wire ropes at two ends of main girder bottom cover plate by fixed support, make main girder bear a bending
moment (main girder upper half bears tensile stress, lower half press stress), and main girder recovers up-warp influenced by
the bending moment. When main girder bears loads, working pressure is rightly opposite to the steel bar pre-stressing force which
at the same time can counterbalance part of working press stress, thus improve load capacity of main girder.
